Boost backfire rough idle

I have. Just got it back from gns coupe weeks ago. I've tweaked it advanced from were the light come on. Maybe I'll try to retard it a bit
I just endured a similar process - I know exactly how you feel. Changed everything, new 60# injectors, coil pack / module, ECM, plug wires, plugs, volt booster, Hot Wire, chips, multiple MAF's, cam sensor, crank sensor, smoke test, vacuum test, known good alternator, compression test, Blue Top Injectors and Chip - changed everything - it has taken all year and all my money.

My Translator was bad, yours might be also. Swap it out for a known good one. You have changed everything BUT the Translator - change it too.

In my case I had the old Translator Plus (v4.0) with the EST pigtail. Removed the EST pigtail, soldered the timing wire back to stock, (the wire behind the glove box) swapped in a known good translator (v5.0)...not one pop or sputter since. Miracle...changed my life

I have since upgraded to Translator 6.25 (current version like yours) I threw that old Translator Plus and EST wire into the trash like a dead animal.

Here's the good news - when you DO find the issue - it will run like a velvet gorilla - why? Everything will be known good.

Keep at it, the good stuff is just around the corner.
Thanks mile high! Got ahold of new friend this am to swap in his translator when I get home next week. My ecm might be back fm Bob by then. If not he has a low ohm ecm I can try.....nice to make new friends locally that willing to help out. Easier on my wallet for sure....
Had similar problem with our car back in '99. Tried everything we could think of , then one day while on lift we noticed the heat shield for starter was loose. The little metal plate that bolts to the block just above the was loose and was randomly hitting the positive battery post on the starter; we tightened it up and problem went away.

Hope you find it, as these things can be frustrating.

Thanks Bob.... I ran new power and ground from Caspers. Everything secured well. Dam cars super frustrating at this point. Shoveled alotta money in the ol girl..gonna try a different translator and ecm when I get home. Hopefully get some favorable results. Powerlogger and wide band should be there as well.
Thought I'd get back to everybody with a good Buick life lesson. Always sucks when you read posts, and know the guy fixed his problem but never posted what it was. After replacing the ccci connection, the car still backfired. I found the brand new ac delco coil was toast, also my spare brand new ac delco had one leg at 6.4ohm's! Wtf! Now have autozone coil, runs bitchn. Total shock! 2 new bad ac's in a row? Maybe I got some out of a bad batch? Have to hang my head a little on this one. Guess the moral of the story, check"new" parts if able, and go back to the basics when your not getting anywhere. Probably had a max of 1hr run time on that dam coil, unbelievable..... Thanks for the input from everyone, really appreciated the knowledge that was shared.
Sam Memolo always says that new stands for "never ever worked". I have learned this lesson the hard way too. So don't feel like you are alone in your misery. Glad you found the problem. brand new ac delco coil was toast, also my spare brand new ac delco had one leg at 6.4ohm's!

BTDT! Aggravating as %$#@!
I went thru 3 new, BWD modules at Advance ap. I got snookered the first time, by taking it home, and then testing w/ the Casper's tool. Back to Advance, along w/ my tool. I set it up on the counter, hooked up the coil pak, {he had 2}, and showed the counter guy. He got a 3rd, went back, same stuff. Said screw this, and ordered an original Delco from Hiway stars, along w/ a new coil.. Wala!

That tester has pd for itself many times over!(y)